The present invention relates to refractory moldable compositions and, more particularly, to a dry, lightweight refractory mixture which upon the addition of water becomes plasticized to yield a moldable, air-setting, insulating refractory composition which may be readily formed into various ceramic objects.
Various lightweight, insulating ceramic fiber refractory compositions are available in preformed shapes, blankets, bricks and panels. These materials are frequently used in furnace interiors because their lightweight reduces heat storage and therefore conserves fuel and reduces furnace heat-up time. Unfortunately, the use of such refractory compositions is limited to relatively simple shapes and to applications such as lining industrial furnaces and the like.
To complement such ceramic fiber refractory products of definite dimensions, wet, moldable insulating refractory compositions consisting of ceramic fiber, a thickening agent, and adhesion enhancing agent, and a liquid vehicle carrier have been developed. Wet, moldable insulating refractory compositions of such a type are molded into the desired shape in-place in the desired location. The liquid vehicle carrier is then evaporated from the moldable refractory composition with heated air so as to set the refractory composition in its final shape. It is necessary that moldable refractory compositions of this type be non-setting at ambient air temperatures because such moldable refractory compositions are produced, shipped and stored in a wet form containing the liquid vehicle carrier.
It is therefore an object of the present invention to provide a dry, lightweight refractory mixture which can be shipped and stored in a dry form, but which becomes plasticized upon the addition of a liquid vehicle, such as water, to yield a moldable, air-setting, insulating refractory composition.
It is a further object of the present invention to provide a dry, lightweight refractory mixture which upon the addition of water yields a moldable composition which air-sets within a relatively short period, such as eight hours, but remain readily moldable after mixing with water for sufficient working time to permit troweling, tamping, ramming and other forming operations to be performed prior to setting.